what should the short and long fuel trim be? And what is considered too high and too low to cause damage to the engine and components of the exhaust?
Clarification: Is there an issue with the vehicle, or you are just asking out of curiosity? It’s a good question.
Generally speaking, you’d want to be as close as possible to 0% for both at idle - but there is no such thing as a perfect car especially as it ages. So, the next best is within +/- 5% (at idle). Some will say +/- 10%. However, on most vehicles a code may not be tripped (for running too rich or too lean) until the fuel trims exceed +/- 20 to 25%, so it’s a good idea to periodically plug in the scan tool and see how you are doing on fuel trims and not wait for a code to be thrown.
On Toyota’s, even at over 100,000 miles Scotty has shown the fuel trims in some of his videos to easily be within +/- 5%. Some of those videos showed them even within +/- 2%, but I wouldn’t worry unless you are outside +/- 10%.
See below:
https://scanneranswers.com/read-live-data-from-obd-ii-scan-tools/
And that is +-10% for both?
Yes, and as a general rule of thumb. But as I said, on Toyota’s that are well maintained it should not get that high. On a GM vehicle, it’s a different story.
Year, make, model, engine, mileage?????????
96, Toyota Camry, 2.2L Automatic.